Differential diagnosis of abnormal enlargement and bending deformities in the skeleton of a medieval child from St Peter's Church cemetery, Riga, Latvia

The aim of this research was to consider differential diagnoses for extensive skeletal deformities in the skeletal remains of a child, suggestive of a severe condition compromising the bone structure. The individual was excavated from a medieval cemetery in Riga, Latvia (15th-16th centuries AD) in 2004. Macroscopic, radiographic and biomolecular analyses were carried out on the remains. Macroscopic analysis revealed that the anterior deciduous dentition was missing ante-mortem, with the alveoli almost completely remodelled. Cortical thickening was observed on the long bones of the arms and legs, and on the ribs, and thickening of the diploic space was observed in the skull. Most bones of the skeleton were enlarged and porous. Marked bending deformities of the long bone shafts, as well as the os coxae and ribs, were also present. Radiographic analysis revealed healed fractures of the right humerus and left tibial diaphyses. Biomolecular analysis confirmed that the child was a girl. Based on the appearance of the lesions, diagnosis concentrated on healed rickets (childhood vitamin D deficiency), while juvenile Paget's disease and osteogenesis imperfecta were considered as differential diagnoses. In the palaeopathological literature, it is rare to find such a severe expression and long-standing form of possible healed rickets, especially in a population with a low prevalence of the condition. Poor DNA preservation prevented the ability to explore whether the differential diagnoses had any genetic origin.